Rising sea levels from climate change pose a serious threat to coastal cities around the world, but national parks are also at risk.

A new report from the National Park Service says sea level rise at 40 coastal national park sites, including eight in California, will put $40 billion worth of assets at high exposure. The estimate, it said, is almost certainly on the low side.

However, “A quick reassessment of the methodology contained within this report following Hurricane Sandy suggests that we have been conservative in labeling an asset as high exposure."

The report assumes that sea levels would rise 1 meter, or 3.28 feet, in the next 100 to 150 years. That’s a number it is more comfortable projecting than the actual elevations of the assets. The executive summary (pdf) closes with a warning that the report should not be used for decision making at the unit level because accurate elevation data was unavailable for the “vast majority” of the assets from its chief source, the already-existing Facilities Management Software System (FMSS) (pdf) database.

That said, 39% of the assets are labeled high exposure. Parks in the Southeast U.S. are the most vulnerable, with 100% of assets in nine of the 13 park units at “high” risk. The Northeast was next worse, followed by the Pacific West and Intermountain regions.

Six of California’s park units are “low,” two are “intermediate” and none are at “high” risk, although assets within them get the scary high rating.

Golden Gate National Recreational Area has the most assets at risk. Eighty-nine percent of its 1,049 assets are deemed “low” risk and 11% “high” with a “current replacement value” of $617.6 million.